I wouldn't normally recommend installing any CBU on concrete, but this should work fine for a small area if you do it right. You now know that you have to completely weigh it down however. Once the mortar skinned-over it'll have no bonding power. You need to rip it up and start over.
I'm not sure you needed to do that in the first place though. You know you need to install a wood molding where the laminate and tile meet, don't you? The laminate should be installed short of the tile to allow expansion, and the proper molding will cover the gap.
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