#Biztalk Kill Process associated with BizTalk Host Instance
$processID = Get-WmiObject Win32_Service -Filter "Name='BTSSvc`$BizTalkServerApplication'" | Select-Object -Expand ProcessID
Write-Host "processID=$processID"
stop-process -id $processID -Force
Write-Host "Completed"

This can be used to kill a BizTalk Host Instance that is in the stop-pending state.

Other commands you can run to see how the Get-WmiObject Win32_Service works:

#get-wmiobject Win32_service
#get-wmiobject Win32_service | where {$_.Name -match "BizTalkServerApplication"}
#get-wmiobject Win32_service | where {$_.Name -eq "BTSSvc`$BizTalkServerApplication"}