You have it backwards. SWAT police move aggressively, at great personal risk, in order to save civilian lives. The idea is that there is a hostage situation and hostages are being actively killed.
And are they actually taking great personal risk? Police killed a bit under 1000 people in the US in 2016 and had around 150 officers die (with lots of this vehicle related). Seems like it's riskier for people interacting with cops than the cops themselves.