A group of student protesters trapped inside Hong Kong’s Polytechnic University attempted to escape through the sewers on Wednesday, but the effort was thwarted when firemen sealed the manhole they were trying to use.

About a hundred protesters are stuck inside the university, which is surrounded by riot police. Over a thousand of them were arrested after surrendering or making failed escape attempts, some of them quite spectacular, such as the group that tried abseiling from a bridge to be picked up by waiting motorcycles below. The remaining protesters have used archery and firebombs to hold the police at bay.

The group that tried using the sewers to escape equipped themselves with waterproof boots and torches to brave rising water levels, sewage, and vermin, but could not get past manholes blocked by the fire department.

“The sewer was very smelly, with many cockroaches, many snakes. Every step was very, very painful. I’d never thought that one day I would need to hide in a sewer or escape through sewers to survive,” a 21-year-old student told Reuters.

“After all of the things that happened, I don’t think protesters taking control of the universities was a good option. We don’t have gear like the police. We are not well-organized like the police,” another protester conceded, adding that he felt bad about damage to the university.

The plan was for protesters to dig in on five universities, using them as safe bases from which they could block roads and conduct demonstrations, retreating to their campus redoubts to avoid arrest. The resulting police sieges of several universities greatly increased tensions in Hong Kong.

The 60th edition of the Hong Kong Open golf tournament, originally scheduled to begin on November 28, was postponed on Wednesday due to ongoing disruptions in the city. Tournament sponsors said they would attempt to reschedule the tournament for sometime early in 2020. Similar tennis and squash events have also been canceled during the protests.

The U.S. Senate on Tuesday unanimously passed the Hong Kong Human Rights and Democracy Act, which requires more careful scrutiny of China’s respect for human rights in Hong Kong before annual renewal of the city’s special trade privileges and allows tough sanctions against Chinese officials who violate human rights or compromise Hong Kong’s autonomy.

The Chinese government responded with fury, charging that the bill “neglects facts and truth, applies double standards and blatantly interferes in Hong Kong affairs and China’s other internal affairs.”

“China will have to take strong countermeasures to defend our national sovereignty, security and development interests if the US insists on making the wrong decisions,” said a statement from the Chinese Ministry of Foreign Affairs.

Chinese Vice Foreign Minister Ma Zhaoxu summoned William Klein, counselor for political affairs at the U.S. embassy in Beijing, on Wednesday to make “stern representations” about the Senate bill and demand the U.S. stop “meddling” in China’s affairs. Ma told Klein that China will retaliate if President Donald Trump signs the bill into law.

Meanwhile, the British government summoned the Chinese ambassador to express outrage over the “disgraceful mistreatment” of Simon Cheng, a Hong Kong citizen working for the U.K. consulate who said he was detained and tortured during a visit to mainland China in August.

The Chinese government snapped back that it “absolutely cannot accept the U.K. government’s interference in this case” and promised to summon the British ambassador to express its “opposition and anger” at British meddling in Hong Kong politics.

“We hope the UK will be prudent and stop interfering in Hong Kong and in China’s domestic affairs because it will, eventually, only harm the U.K.’s own interests,” the Chinese Foreign Ministry said.

Cheng, a trade and investment officer for the British consulate, volunteered to do some overtime work studying the Hong Kong protest movement and its social media communications. Cheng set up a trip by rail to Shenzhen for a business conference in August and walked right into the trap feared by pro-democracy activists in one of Hong Kong’s biggest controversies before the protests broke out: Chinese police working in the Shenzhen departure area of Hong Kong’s West Kowloon train station searched his phone, found protest material stored upon it, arrested him, and shipped him back to China for brutal interrogations.

Cheng said he was beaten, hung from the ceiling in chains, deprived of sleep, forced to assume stress positions, compelled to sing the Chinese national anthem, and eventually forced to make videotaped confessions. He said the Chinese secret police wanted him to identify protesters they could arrest, and said other Hong Kongers were tortured alongside him.

“I saw a bunch of Hong Kong people getting arrested and interrogated. I heard someone speak in Cantonese saying: ‘Raise your hands up – you raised the flags in the protest didn’t you?’” Cheng recalled.

Cheng believes he was released because of international media attention on his case and pressure from the British government. He felt it was too dangerous for him to return to Hong Kong, describing himself to the South China Morning Post on Wednesday as an asylum seeker.

Hong Kong’s pro-Beijing government seemed disinclined to help Cheng, with Justice Secretary Teresa Cheng Yeuk-wah advising him to file a complaint with Chinese authorities.

“There are many things that are often reported and sometimes it is extremely important to gather the whole facts and veracity of it before any view is to be formed, so I prefer to hold my opinion until I have the opportunity to collect and analyze any information that I might have,” she said.