Its a double edged sword. Jagmeet stays on and gets his pension and half ass "stands up to" Trudeau, however the party will only decline even further.
Call an election now and if lucky, the NDP gains a seat or 3, Jagmeet must aggressively campaign against Trudeau (Even CBC has been saying people see the two parties as one) and show WHY he is a third option. He could use the rail strike as his lead in to breaking the coalition.
People need to see Jagmeet (and the NDP) as a viable third option and he isn't viewed that way right now.