Alternative sources:
Former IDF soldiers attack pro-Palestinian student protesters at Columbia University
https://www.wsws.org/en/articles/2024/01/22/lfsy-j22.html
Columbia Students Allegedly Sprayed With Putrid Chemical at Pro-Palestine Rally
Columbia Scolds Students for “Unsanctioned” Gaza Rally Where They Were Attacked With Chemicals
https://theintercept.com/2024/01/22/columbia-university-palestine-protest-skunk/
Given that only 68 people died to Hamas rocket attacks ever, probably the latter.