Ok think I may have found a bit of a chink the armour.
Looks like they have already used a large portion of that $450m.
They have paid $176m to repay some debt and purchased $150mil of PPE when compared to $60mil in FY 17
This could present some issues if the deal doesn't go through this week, they will need to find another deal, which is a bit cheaper, or hope they can offer up some of their stock + Cash.
Either that or they do a share buyback, which wouldn't be terrible given how far the stock price has fallen.