[zip1234]

A military unit may have to go do something with high casualties in order to achieve a higher objective.

[ludamad]

I wonder at what point you typically realize you've been put on a high-chance-of-casualty mission

[gonzo41]

When your mission prep includes pre-applying tourniquets to your arms and legs before you go for a drive.

[Sharlin]

Usually when you or your unit is told to take point. Or more generally, act as a forward element of some sort.