"Can it wait for a minute? I'm in the middle of some calibrations."
Everyone's favourite ex-C-Sec, ex-vigilante then military adviser dude against the Reaper threat wants everyone to stay calm while he calibrates. Calibrating everything. His name is Garrus Vakarian and this is his favourite t-shirt from the Citadel.
Okay, that's a lie. I made that up.
Drawn in Adobe Illustrator before being finalised in Adobe Photoshop. Crown and text is based off traditional "Keep Calm" meme shirts, but Garrus head is drawn from scratch.
Black text version for lighter t-shirts is available here - http://www.redbubble.com/people/cr33g/works/12123569-keep-calm-and-calibrate-black-text