Well it wouldn't exactly be a big tragedy if Umarov happened to get killed by accident when he was captured. Surely it's only a matter of time until they get him.
But I am against the death penalty on principle.
It is very surprising though, that a country like Russia can't manage locate a well known person inside its own territory. Maybe with a bit more brutality on part of security services, it would be possible... but then, that would start a dangerous precedence. Hope they get him before he tries again.