My guess - ML was happy to see MC again (since it's been a while) and knew he'd been drinking so was hoping to maybe get a little more flirting/something more from ML, that's why he was slightly disappointed when ML said he'd only had a little to drink. ML needs to stop leading MC on - they clearly like each other, don't know why ML keeps messing with MC like this.
My guess - ML was happy to see MC again (since it's been a while) and knew he'd been drinking so was hoping to maybe get a little more flirting/something more from ML, that's why he was slightly disappointed when ML said he'd only had a little to drink. ML needs to stop leading MC on - they clearly like each other, don't know why ML keeps messing with MC like this.